The fit projections for the m(K++) and mJ/(K++) distributions are shown in Fig. J. Rev. Horgan, R. R., Liu, Z., Meinel, S. & Wingate, M. Calculation of B0K*0+ and \({B}_{s}^{0}\to \ \ \phi {\mu }^{+}{\mu }^{-}\) observables using form factors from lattice QCD. A. Bertolin. Google Scholar. The hierarchical effect needed to explain the existing \(\overline{b}\to \overline{s}{\ell }^{+}{\ell }^{-}\) and \(\overline{b}\to \overline{c}{\ell }^{+}{\nu }_{\ell }\) data, with the largest effects observed in tau modes, then muon modes and little or no effects in electron modes, suggests that studies of \(\overline{b}\to \overline{s}{\tau }^{+}{\tau }^{-}\) transitions are also of great interest69,70. The consistency of this ratio with unity demonstrates control of the efficiencies well in excess of that needed for the determination of RK. Bezshyiko,A. Buonaura,D. De Simone,V. Denysenko,J. Eschle,M. Ferrillo,D. Lancierini,O. Lantwin,A. Mathad,K. Mller,P. Owen,N. Serra,R. Silva Coutinho,O. Steinkamp&Z. Wang, Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK, T. Ackernley,T. J. V. Bowcock,G. Casse,A. J. Chadwick,C. A. Chavez Barajas,K. Dreimanis,S. Farry,V. Franco Lima,T. Halewood-leagas,J. P. Hammerich,T. Harrison,K. Hennessy,D. Hutchcroft,P. J. Marshall,J. V. Mead,K. Rinnert,E. Rodrigues,T. Shears,K. A. Thomson,E. Vilella Figueras,H. M. Wark&L. E. Yeomans, Instituto Galego de Fsica de Altas Enerxas (IGFAE), Universidade de Santiago de Compostela, Santiago de Compostela, Spain, B. Adeva,P. Baladron Rodriguez,O. Boente Garcia,A. Brea Rodriguez,A. Casais Vidal,V. Chobanova,X. Cid Vidal,J. Dalseno,L. Dieste Maronas,A. Fernandez Prieto,A. Gallas Torreira,B. Garcia Plana,A. Giovent,J. Lomba Castro,D. Martinez Santos,C. J. Parkinson,M. Plo Casasus,C. Prouve,M. Romero Lamas,A. Romero Vidal,J. J. Saborido Silva,C. Santamarina Rios,S. Sellam,R. Vazquez Gomez&P. Vazquez Regueiro, H.H. The results supersede those of the previous LHCb analysis. Rev. 2016, 65 (2016). High Energy Phys. In addition to affecting the decay rates, new physics can also alter how the decay products are distributed in phase space. C 79, 840 (2019). The distributions of the B+ transverse momentum (pT, left) and the ratio rJ/ (right) relative to its average value \(< {r}_{J/\psi } >\) as a function of pT. Rev. The LHCb collaboration et al. Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. The significance of this discrepancy is 3.1standard deviations, giving evidence for the violation of lepton universality in these decays. In the remainder of this paper, the notation B+K++ is used to denote only decays with 1.1Test of lepton universality in beauty-quark decays The effect on RK is at the 1% level. Lett. The shape of the B+J/+ background contribution is taken from simulation, but the size with respect to the B+J/K+ mode is constrained using the known ratio of the relevant branching fractions2,94 and efficiencies. The detector includes a high-precision tracking system with a dipole magnet, providing measurements of momentum and impact parameter (IP), defined for charged particles as the minimum distance of a track to a primary protonproton interaction vertex (PV). 2014, 125 (2014). Agostinelli, S. et al. High Energy Phys. The y-axis in each figure shows the number of candidates in an interval of the indicated width. All contributing authors, as listed at the end of the manuscript, have contributed to the publication, being variously involved in the design and construction of the detector, writing software, calibrating sub-systems, operating the detector, acquiring data and analysing the processed data. Capdevila, B., Descotes-Genon, S., Hofer, L. & Matias, J. Hadronic uncertainties in BK*+: a state-of-the-art analysis. High Energy Phys. The ATLAS collaboration et al. Lett. Isidori, G., Nabeebaccus, S. & Zwicky, R. QED corrections in \(\overline{B}\to \overline{K}{{{{\rm{\ell }}}}}^{+}{{{{\rm{\ell }}}}}^{-}\) at the double-differential level. The y-axis in each figure shows the number of candidates in an interval of the indicated width. Right: a possible new physics contribution to the decay with a hypothetical leptoquark (LQ) which, unlike the electroweak bosons, could have different interaction strengths with the different types of leptons. 12, 131 (2014). PDF Test of lepton universality in beauty-quark decays - arXiv The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. The 1.9% uncertainty on the B+J/K+ branching fraction2 gives rise to the dominant systematic uncertainty. J. The SM is unable to explain cosmological observations of the dominance of matter over antimatter, the apparent dark matter content of the Universe, or the patterns seen in the interaction strengths of the particles. Geant4 developments and applications, IEEE Trans. These fractions are observed to agree well with those observed in resonant events selected from the data. In summary, in the dilepton mass-squared region 1.1Test of lepton universality in beauty-quark decays A. Rodriguez Lopez, Universitt Bonn Helmholtz-Institut fr Strahlen und Kernphysik, Bonn, Germany, Hanoi University of Science, Hanoi, Vietnam, P.N. J. Instrum. Measurements of branching fractions, rate asymmetries, and angular distributions in the rare decays BK+ and BK*+. Test of lepton universality in beauty-quark decays, arXiv:2103.1176 . Particle Physics (4th ed. This double ratio is expected to be close to unity2 and is determined to be 0.9970.011, where the uncertainty includes both statistical and systematic effects, the former of which dominates. One method to search for new physics is to compare measurements of the properties of hadron decays, where hadrons are bound states of quarks, with their SM predictions. Fan,Y. Gan,G. Gong,C. Gu,F. Jiang,Y. Kang,X. Liu,Y. Luo,H. Mu,Z. Ren,J. Wang,M. Wang,Z. Wang,L. Xu,D. Yang,Z. Yang,M. Zeng,L. Zhang&X. Zhu, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK, P. E. L. Clarke,R. Currie,S. Eisenhardt,S. Gambetta,K. Gizdov,S. E. Mitchell,F. Muheim,M. Needham,S. Petrucci,G. Robertson,M. R. J. Williams&J. Aubert, B. et al. The electron and muon veto cuts differ given the relative helicity suppression of ++ decays. J. Bainbridge, R. on behalf of the CMS collaboration Recording and reconstructing 10 billion unbiased b hadron decays in CMS. Measurement of the ratio of branching fractions \({{{\mathcal{B}}}}({\overline{B}}^{0}\to {D}^{* +}{\tau }^{-}{\overline{\nu }}_{\tau })/{{{\mathcal{B}}}}({\overline{B}}^{0}\to {D}^{* +}{\mu }^{-}{\overline{\nu }}_{\mu })\). Lyon, J., & Zwicky, R. Resonances gone topsy turvythe charm of QCD or new physics in bs+? B-decay discrepancies after Moriond 2019. A. Measurable quantities can be predicted precisely in the decays of a charged beauty hadron, B+, into a charged kaon, K+, and two charged leptons, +. The corresponding parameters are then fixed in the fits to the relevant non-resonant modes. Explore our virtual experience Novel Tests of Lepton Universality Boost Evidence for 'New Physics To obtain CERN experiment found that beauty quarks not behaving in the way they There are excellent prospects for all of the above and further measurements with the much larger samples that will be collected with the upgraded LHCb detector from 2022 and, in the longer term, with the LHCb Upgrade II71. Belyaev, I. et al. 331, 032023 (2011). 2019, 89 (2019). Lett. The muon BDT classifier has similar performance. Such studies can help to explain the matter-antimatter asymmetryof the Universe. In December 22 the LHCb collaboration announced that the results of a new analysis of bs decays show an agreement with the SM. Test of lepton universality with beauty baryons, RpK The calibrated simulation is used subsequently to obtain the m(K++) mass shape and relative fractions of these background components. Background from other exclusive B-hadron decays requires at least two particles to be misidentified. A test statistic is constructed that is based on the likelihood ratio between two hypotheses with common (null) or different (test) RK values for the part of the sample analysed previously (7, 8 and part of the 13TeV data) and for the new portion of the 13TeV data. Systematic uncertainties affecting the determination of the signal yield are assessed using pseudo-experiments generated with variations of the fit model. Reassessing the discovery potential of the B + K + + l + +l - decays in the large-recoil region: SM challenges and BSM opportunities, Physical Review D93: 014028. arXiv:1412.3183. Test of lepton universality using \({\Lambda }_{b}^{0}\to p{K}^{-}{\ell }^{+}{\ell }^{-}\) decays. Phys. Energy Phys. Phys. The B+ hadron contains a beauty antiquark, \(\overline{b}\), and the K+ a strange antiquark, \(\overline{s}\), such that at the quark level the decay involves a \(\overline{b}\to \overline{s}\) transition. the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Energy Phys. 1, right) and could have non-universal interactions, hence giving branching fractions of B+K++ decays with different leptons that differ from the SM predictions. 2,65), the RK ratio is determined via the double ratio of branching fractions, In this equation, each branching fraction can be replaced by the corresponding event yield divided by the appropriate overall detection efficiency (Methods), as all other factors needed to determine each branching fraction individually cancel out. High. The residual contribution from such decays is considered as a source of systematic uncertainty. High. Evidence for an excess of \(\overline{B}\to \ \ {D}^{(*)}{\tau }^{-}{\overline{\nu }}_{\tau }\) decays. Test of lepton flavour universality in beauty-quark decays Phys. The departure of the profile likelihood shown in Extended Data Fig. So far, LHCb has collected 260 billion bottom-quark antiquark pairs in experimental runs using protons with 7 and 8 tera-electron-volt (TeV) center-of-mass energies. Search for lepton-universality violation in B+K++ decays. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Kou, E. et al. J. Phys. The Large Hadron Collider (LHC) is the worlds highest-energy particle accelerator and is situated approximately 100m underground, close to Geneva, Switzerland. 2020, 083C01 (2020). Blum, A., Kalai, A. Jan 2019; PHYS REV LETT; Zenodo https://doi.org/10.5281/zenodo.4587748. Ser. 04, 016 (2017). Rev. 3, S08005 (2008). On Drell-Yan production of scalar leptoquarks coupling to heavy-quark Altmannshofer, W., Niehoff, C., Stangl, P. & Straub, D. M. Status of the BK*+ anomaly after Moriond 2017. (Top) distributions of the reconstructed spectra of (left) the angle between the leptons, (+,), and (right) the minimum pT of the leptons for B+K++ and B+J/(+)K+ decays. & Virto, J. A distinctive feature of the SM is that the different leptons, electron (e), muon () and tau (\(\tau^{-}\)), have the same interaction strengths. The trigger response is corrected using weights applied to simulation as a function of variables relevant to the trigger algorithms. D 69, 074020 (2004). Comput. Test of lepton universality in beauty-quark decays LHCb collaboration Nature Physics 18 , 277-282 ( 2022) Cite this article 8068 Accesses 76 Citations 29 Altmetric Metrics Abstract. 199, 86101 (2016). Even though the non-resonant and resonant samples are mutually exclusive as a function of q2, there is significant overlap between them in the quantities on which the efficiency depends, such as the laboratory-frame momenta of the final-state particles or the opening angle between the two leptons. The results are consistent between the different data-taking periods and with previous LHCbmeasurements37. Aaij, R. et al. High. Google Scholar. Test of lepton universality in beauty-quark decays - ResearchGate ISSN 1745-2481 (online)
Philadelphia Navy Yard Dry Dock,
Boris Johnson Voice Generator,
How Much Is A 1943 Wheat Penny Worth,
Articles T
